An existing ground fault circuit interrupter, for example as disclosed in Chinese Patent Application No. 201010248157.8, includes a shell, an output conductor, a power input end, a power output end, and a reset button. The reset button is used to close a main circuit switch and matches with a lock catch mechanism to keep a closed state of the main circuit switch and enable the power input end, the power output end, and the output conductor to be kept conductive. It also includes an electromagnetic trip mechanism used for disconnecting the main circuit switch when a leakage current is generated. At least two elastic metal sheets extend from the input end and the output end of the existing ground fault circuit interrupter. Each elastic metal sheet is of a certain length. One end of each elastic metal sheet is secured, and the other end of each elastic metal sheet is freely suspended. The free end of each elastic metal sheet is bent at a certain angle relative to a secured end, and movement of each elastic metal sheet is driven by a pressing or lifting action of other components to be in conductive contact with a corresponding static metal sheet. The main supply includes a neutral line and a live line.
In manufacturing, it is difficult to consistently achieve the desired degree of bending the respective elastic metal sheets. Further, it is difficult to maintain consistency in the degree of bending of left and right elastic metal sheets because the free ends repeatedly and elastically rise; strain deformation may be caused after substantial use. Indeed, such repeated elastic rise may undermine the reliability of expected conductive contact, resulting in a potential safety hazard. Additionally, manufacturing and assembly of the elastic metal sheets are relatively complex, the amount of materials required is substantial, and there is a high failure rate in manufacturing the elastic metal sheets.
Chinese Patent Application No. 201410499136.1 discloses an improved ground fault circuit interrupter. That application teaches including a movable metal sheet structure is elastically arranged with a lifting plate. The reset button drives the lifting plate to lift up the movable metal sheet structure by hooking it with the lifting plate with a lock catch. This enables an end of the movable metal sheet to be placed in conductive contact with a static contact end of its corresponding static contact metal sheet.
Such structure still has certain limitations: First, to reliability and accurately enable such lifting and closing, the manufacturing and assembly is difficult and highly technical. Second, numerous components, including a flexible wire and a transition metal must be connected in complex structure, which results in high manufacturing costs. Third, an on-off mode of lifting and closing is only accomplished by overcoming resistance of a reset spring on the reset button; this is time consuming and the spring is at risk of straining. Fourth, a locking piece of the lock catch is in a block shape and does not have a mechanism to prevent the locked piece from being disengaged.
A solution for at least some of the above-described problems is disclosed in Chinese Patent Application No. 201510036392.1. There, the disclosed ground fault circuit interrupters with a reversed wiring protection implement tripping when in reversed wiring through electric structures—including a control chip, a thyristor and the like. However, such electrical structures must be intact to operate. That is, the devices cannot effectuate reversed wiring protection if key elements, including the thyristor, are damaged. The devices lack a mechanical forced tripping function if the main circuit switch is in the closed state. Thus, such disclosed ground fault circuit interrupters also embody potential safety hazards.